1. Field of the Invention
This invention relates to zippers or slide fasteners and more particularly to a separable type of slide fastener having a separable terminal assembly.
2. Prior Art
There have been proposed many separable slide fasteners equipped with a separable terminal assembly which comprises a separable pin fixed to the bottom end of one of companion stringer tapes, a retainer pin fixed to the bottom end of the other stringer tape and a retainer formed integrally with the retainer pin for receiving the separable pin to couple the two stringer tapes. It is a common practice in such slide fasteners to anchor the opposed endmost coupling elements to the separable terminal assembly with a view to preventing the coupling elements from falling off from the stringer tapes.
However, an inevitable disadvantage of such fastener is that the pins of separable terminal assembly respectively fixed to the tapes adjacent to or substantially integral with the endmost coupling elements tend to hinder the smooth engagement or disengagement of the endmost coupling elements, when a slider moves toward and away from the separable terminal assembly to open and close the fastener. In some instances, the slider is blocked at a position just before the separable terminal assembly. The starting movement of the slider in the fastener closing direction is also liable to become sluggish, sometimes even impossible. This problem is aggravated where the separable terminal assembly and the coupling elements are both made of a plastic material, the endmost coupling elements are susceptibly to deformation under heat and pressure applied during fusion of the separable terminal assembly with the endmost coupling elements.
U.S. Pat. No. 3,162,918 discloses a somewhat successful improvement of a separable slide fastener having a row of coupling loops or a coil element which includes a flexible plastic finger integrally molded with a body portion of a separable terminal assembly and extending along the edge of the stringer tape through the coil, the resulting terminal assembly providing secure but relatively flexible connection with the lower portion of the coupling elements. Such arrangement however requires the use of molds precisely finished to fit tightly over the loops of coupling elements and the maintenance of finely controlled molding temperature and pressure conditions, resulting in complicated and costly process and increased consumption of material.